Problem: Solve the following expression and give your answer as a fraction. $ \dfrac{42}{100} \times -0.45 \times -0.2 = {?} $
Solution: First get all of the numbers as simplified fractions. $ \dfrac{42}{100} = \dfrac{21}{50} $ $ -0.45 = -\dfrac{4.5}{10} = -\dfrac{9}{20} $ $ -0.2 = -\dfrac{2}{10} = -\dfrac{1}{5} $ Now we have: $ \dfrac{21}{50} \times -\dfrac{9}{20} \times -\dfrac{1}{5} = {?} $ $ \phantom{ \dfrac{21}{50} \times -\dfrac{9}{20} \times -\dfrac{1}{5}} = \dfrac{21 \times -9 \times -1} {50 \times 20 \times 5} $ $ \phantom{ \dfrac{21}{50} \times -\dfrac{9}{20} \times -\dfrac{1}{5}} = \dfrac{189}{5000} $